Disable Vc if architecture is not x86_64
Disable Vc if architecture is not x86_64

Vc only supports x86_64, but the previous condition allowed it to be
enabled on x86 systems, breaking the build.

olifre/root,root-mirror/root,olifre/root,zzxuanyuan/root,karies/root,root-mirror/root,olifre/root,zzxuanyuan/root,karies/root,root-mirror/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,zzxuanyuan/root,olifre/root,olifre/root,root-mirror/root,olifre/root,zzxuanyuan/root,zzxuanyuan/root,karies/root,zzxuanyuan/root,zzxuanyuan/root,root-mirror/root,zzxuanyuan/root,karies/root,zzxuanyuan/root,karies/root,olifre/root,root-mirror/root,karies/root,olifre/root,zzxuanyuan/root,karies/root,root-mirror/root,root-mirror/root,zzxuanyuan/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,karies/root,zzxuanyuan/root